Baris Sayin

The Effects of Different Types of Fly Ash on the Compressive Strength Properties of Briquettes

The aim of this study is to evaluate the effect of the different types of fly ash on the compressive strength properties of sintered briquettes. Thermal gravimetric (TG) analysis was carried out. The chemical composition and physical properties of the materials used were determined. Particle size distribution and microstructure elemental analyses of the materials used were carried out by a particle size analyzer (Mastersizer) and a scanning electron microscope (SEM-EDS). Following the characterization of the materials, briquettes were prepared by sintering at different temperatures. Compressive strength test results of the briquette samples indicated that briquettes with a compressive strength value of 47.45 N/mm2 can be produced. The results obtained exceed the Turkish standard (TS EN 771-1) requirements (9.8–23.54 N/mm2). SEM-EDS results showed that briquette samples made with Tuncbilek (T) fly ash had a higher percentage of the glassy phase than the other briquette samples. Due to this microstructure, it results in higher compressive strength value.

An Investigation of Interfacial Stresses in Reinforced Concrete Beams Using FRP Laminates

Reinforcement of reinforced concrete (RC) beams against bending through utilization of bonded fibre-reinforced plastic (FRP) laminates has been accepted as an effective method of strengthening. In this study, the effects of FRP reinforcement over the parameters of interfacial stresses in reinforced concrete beams were examined both experimentally and numerically. Essentially, the main goal of the study was to investigate quantitatively the behaviour of the RC beams strengthened with adhesively bonded FRP. In order to achieve this goal, an experimental study was initially carried out. Afterwards, the ANSYS® WB finite element program was employed to model and analyze the RC beams externally bonded to FRP. The obtained results are expected to demonstrate the main characteristics of interfacial stress distributions inside beams strengthened with FRP. The evaluation of interfacial stresses provides the basis for understanding the main characteristics in such beams and for developing suitable design rules.

Optimum tuned mass damper design using harmony search with comparison of classical methods

As known, tuned mass dampers (TMDs) are added to mechanical systems in order to obtain a good vibration damping. The main aim is to reduce the maximum amplitude at the resonance state. In this study, a metaheuristic algorithm called harmony search employed for the optimum design of TMDs. As the optimization objective, the transfer function of the acceleration of the system with respect to ground acceleration was minimized. The numerical trails were conducted for 4 single degree of freedom systems and the results were compared with classical methods. As a conclusion, the proposed method is feasible and more effective than the other documented methods.As known, tuned mass dampers (TMDs) are added to mechanical systems in order to obtain a good vibration damping. The main aim is to reduce the maximum amplitude at the resonance state. In this study, a metaheuristic algorithm called harmony search employed for the optimum design of TMDs. As the optimization objective, the transfer function of the acceleration of the system with respect to ground acceleration was minimized. The numerical trails were conducted for 4 single degree of freedom systems and the results were compared with classical methods. As a conclusion, the proposed method is feasible and more effective than the other documented methods.

The effect of usage of inertia function in particle swarm optimization

Particle swarm optimization (PSO) is a classical metaheuristic algorithm. The initial form of PSO may not suitable for several optimization problems of structural engineering. A basic modification ...

Jaya algorithm based optimum carbon fiber reinforced polymer design for reinforced concrete beams

Jaya algorithm is a newly developed metaheuristic algorithm. It is a single phase algorithm, but effective to converge to the best solution and diverge to the worst solution in a single phase. It is not a parameter effected algorithm since it does not contain any specific parameter except the population number. This algorithm proposed for the structural engineering problem which is a retrofit application. The aim of the optimization is to find the best design of carbon fiber reinforced polymer strips in order to increase the shear capacity of reinforced concrete beam. The proposed algorithm was compared with the algorithm which were previously applied. As a conclusion, Jaya algorithm is a competitive one with the advantages of being an easy method.

Analysis of Cement-Based Pastes Mixed with Waste Tire Rubber

Using the methods of thermal gravimetry, differential thermal analysis, Furier transform infrared analysis, and capillary absorption, the properties of a cement composite produced by introducing waste tyre rubber into a cement mixture were investigated. It was found that the composite filled with the rubber had a much lower water absorption ability than the unfilled one.

Constraint factor in optimization of truss structures via flower pollination algorithm

The aim of the paper is to investigate the optimum design of truss structures by considering different stress and displacement constraints. For that reason, the flower pollination algorithm based methodology was applied for sizing optimization of space truss structures. Flower pollination algorithm is a metaheuristic algorithm inspired by the pollination process of flowering plants. By the imitation of cross-pollination and self-pollination processes, the randomly generation of sizes of truss members are done in two ways and these two types of optimization are controlled with a switch probability. In the study, a 72 bar space truss structure was optimized by using five different cases of the constraint limits. According to the results, a linear relationship between the optimum structure weight and constraint limits was observed.

An assessment of SBS modified asphalt concrete pavements performance features performing numerical analysis

In passenger and freight traffic on the roads, which has the largest share of the hot mix asphalt (HMA) prepared asphalt concrete pavement is one of the most preferred type of flexible superstructure. During the service life of the road, they must provide the performance which is expected to show. HMA must be high performance mix design, comfortable, safe and resistance to degradation. In addition, it becomes a critical need to use various additives materials for roads to be able to serve long-term against environmental conditions such as traffic and climate due to the fact that the way of raw materials is limited. Styrene Butadiene Styrene (SBS) polymers are widely used among additives. In this study, the numerical analysis of SBS modified HMA designed asphalt concrete coatings prepared with different thicknesses with SBS modified HMA is performed. After that, stress and deformation values of the three pavement models are compared and evaluated.

Assessment of the Material Quality of Damaged Structures after Earthquake in Van, Turkey

AbstractTwo earthquakes occurred on October 23 and November 9, 2011, in Van, Turkey, with magnitudes (Mw) of 7.2 and 5.6, respectively. The types of the damage and collapse that occurred in both earthquakes necessitate a detailed examination of the load-bearing elements, which essentially comprise the components of RC buildings, in terms of their material quality. For this purpose, the compressive strengths, X-ray diffraction (XRD), and scanning electron microscopy with X-ray microanalysis (SEM/EDS) were performed on concrete samples collected from the collapsed buildings, with a view to understand the role of the materials in the devastation caused by the earthquakes. Visual observations and the results of the tests showed that there were not only construction and manufacturing failures, but also the strength of the concrete was a crucial factor that contributed to the damage and collapse of the buildings. In addition to these conclusions, results obtained from XRD and SEM-EDS showed that compressive str...

COMPARISON WITH EU PUBLIC PROCUREMENT DIRECTIVE 2004/18/EC AND PUBLIC PROCUREMENT LAW NO.4734 IN DETERMINATION OF ECONOMICALLY MOST ADVANTAGEOUS BID

According to EU Directives and the Public Procurement Law No. 4734 which is implemented in our country, in tenders; transparency, introduce competition, equal treatment, reliability, ensure the control of public opinion, at the appropriate time and under suitable conditions, needs, come to the fore elements of efficient use of resources. Construction work projects, the realization of the required quality by keeping within the budget provided for a specified period, the specified criteria in mind, this consciousness, it is possible to have the choice of contractor. Accordingly, when analyzed the procurement decision-making systematic, the most important factor is playing an active role in decision-making process, to determine of most economically advantageous bid. Aforementioned bid in question is a two-alternative: (a) The most economically advantageous bid on the basis of determining the lowest price, (b) Economically most advantageous bid taking into account the determination of non-price factors. In this study, the EU Public Procurement Directive 2004/18/EC and the Public Procurement Law No. 4734 which is implemented in our country, and specified under the two alternatives was examined by determination of most economically advantageous bid and in this scope, presented models are being implemented by EU member states and our country.